The present invention relates to the pulling of strands of a cable into a conduit.
The pulling of strands of a cable into a conduit is commonly used in a certain number of fields. It is used, for example, although not exclusively, in the post-tensioned prestressed concrete technique, in order to install and then tension multi-strand cables in sheaths of circular cross-section previously incorporated into the concrete, in order to compress the structure.
The pulling is generally carried out with the help of a winch cable to which the strand or strands to be pulled are temporarily fixed.
For certain structures requiring a non-rectilinear prestressing line in particular, such as domes involving a line in the form of an inverted U for example, the conventional method for pulling strands is, however, unsuitable.
During the pulling of one or more fresh strands, it may happen that the winch cable enters the bundle of previously installed strands, in particular in certain non-rectilinear zones of the conduit. This is detrimental to the advance of the winch cable inside the conduit.
The winch cable may even become entangled in some of the previously installed strands. In this case, the separation of the winch cable and the strands may prove particularly complex.
In addition to these drawbacks, damage may also be caused to the previously installed strands on contact with the winch cable, which may for example culminate in the tearing off of any plastic sheath surrounding these strands.
A purpose of the present invention is to propose an improved method for pulling strands.